Breech block mechanism



Dec. 30, 1958 2,866,387

R. E. STERN ETAL BREECH BLOCK MECHANISM Filed Jan. 11, 1957 2 Sheets-Sheet 1 0 2| '5 14 QI/Q a v 7 5,271 UIIIIIIIIIIIIIIIIIIIA INVENTORfi RUFUS D. KEISER BY RUDOLPH E. STERN ATTORNEY S Dec. 30, 1958 R. E. STERN ET AL 2,866,387

BREIECH BLOCK MECHANISM Filed Jan. 11, 1957 2 Sheets-Sheet 2 l4- 27 I3 22 I8 Q g Q Q Y Y /7 y7 71! 25 Q Q 32 5O 20 INVENTORJ;

RUFUS D. KEISER BY RUDOLPH E. STERN ATTORNEYS 2,866,387 Patented Dec. 30, 1958 BREECH BLOCK MECHANISM Rudolph Stern, 'hicago, 111., and Rufus D. Keiser, Stamford, Conn, assignors to the United States of America as represented by the Secretary of the Army Application January 11, 1957, Serial No. 633,809

3 Claims. (CI. 89-17) The invention described herein may be manufactured and used by or for the Government for governmental purposes without payment of any royalty thereon.

This invention relates to a breech block mechanism and has for an object to provide such a mechanism capable of rapid movement in a large caliber gun adapted for use with a compact and lightweight breech block. Another object is to provide a substantially straight line movement for a breech block making rapid operation possible. Another object is to provide a breech block equipped with extractors so that ramming and extracting of the propelling charge may be accomplished without the usual secondary operation. Still another object is to provide a mechanism which does not require a large and heavy breech ring such as in sliding breech blocks. Yet another object is to provide a breech mechanism requiring only a small, light weight configuration of the breech end of the tube, more easily fabricated than the interrupted thread often used on larger guns.

Rapid operation of a small caliber gun has been suggested when its breech block has a substantially straight line movement. However, in such guns the guides along which the breech block slide are generally in the same horizontal plane necessitating raising the ammunition above such guides when loaded. The use of a pivotal thrust element or finger for transmitting thrust on a breech block to a breech ring on a gun at the time of firing has been suggested. In small arms the bolt or breech block is sufiiciently long so that it can be securely held in place by only one of such an element. In larger caliber guns the breech block cannot be made correspondingly long and bulky because to do so would make it too heavy.

Under the present invention, a straight line movement for a breech block has been provided in a construction suitable for large size guns without the breech block being unduly heavy. Specifically, closely spaced locking or thrust elements actuated in a distinctive manner to secure all peripheral portions of the breech block, are used so that there will be no danger of such block tilting and leaking when made axially short and of light weight.

Fig. 1 of the drawing shows a longitudinal section through a preferred embodiment of the present invention with the breech block in closed or firing position.

Fig. 2 is a longitudinal section of the same gun with the thrust elements and holding member within the retaining ring before the breech block has opened.

Fig. 3 is a longitudinal section through the same gun with the breech block leaving its closed position.

Fig. 4 shows the breech block in fully retracted position, the distance between the breech ring of the gun and the breech block being cut away.

The breech block in Fig. 1 is in closed or firing position and held within the gun by thrust or locking elements 12 extending between the breech block 10 and a breech ring 11 of the gun. A holding member 13 retains the thrust elements in their radially outward position for holding the breech block against the thrust during firing. A retaining ring 14 is shown contiguous the end face of the gun and being mounted on vertically spaced guides 15. A tension member or sleeve 16 is secured to the holding member 13 for sliding the same longitudinally away from and toward the gun. A rod 17 is secured to the breech block 10 and located within the sleeve 16. A pin 18 extends through the sleeve and rod for the purpose of constituting an abutment in compressing the spring 19 as the holding member 13 is moved out of the gun. Lugs 20 are located opposite one another on the retaining ring 14 for the purpose of riding on the vertically spaced guides 15. Springs 21 surround these guides and cooperate with the retaining ring 14. A ring 22 on the sleeve serves as an abutment flange for the spring 19, this ring being held against movement to the right by the pin 18. A handle not shown is formed on the sleeve 24, the sleeve in turn being welded to the tension member or sleeve 16. A flange 25 is formed on the end of the rod 17 as shown in Fig. 1.

The conical outer surface of the thrust elements 12 is designated by the numeral 26. The left ends of these thrust elements are shown in the drawing as being socketed in a torodial recess 27 formed in the outer end portion of the breech block. While the left end of the thrust elements 12 are of toroidal shape to fit the sockets 27, the opposite ends of these thrust elements conform to the conical shape 23 constituting the bearing surfaces between the thrust elements and the portion of the breech ring 11 receiving the thrust from the breech block 11?. The holding member 13 is provided with an outer, slightly inclined surface 29 and also with a radially inner ledge 30. Between these surfaces 29 and 30 is a more steeply inclined surface 31 for the purpose of forcing the thrust elements radially outward.

In operation, a pull upon a handle causes the sleeve 24 and the sleeve 16 to be moved to the right causing similar movement of the holding member 13 to the right. As the holding member is moved to the right, it compresses the spring 19 which exerts a pull on the breech bolck 16 through the rod 17. The pull, in addition to residual pressure in the chamber tends to open the breech, causes the thrust elements 12 to slide radially inward on the conical surface 28 and comes to rest on ledge 30 of the holding member. The breech block 10, thrust elements 12 and the holding member 13 then continue to move to the right as a unit. As opening of the breech continues, the thrust elements are sliding in to the retaining ring 14 as shown in Fig. 3. Retaining ring 14 then moves together with the breech block, thrust elements and holding member as shown in Fig. 4, compressing the springs 21 around the spaced guides 15 as this unit is moved far enough away from the breech end of the gun for a propelling charge to be moved in front of the breech block. Some type of latch or locking mechanism not shown will be found convenient to hold a handle and the aforesaid unit in position to the right so that ammunition may he slid into position on the face of the breech block. Upon release of the retaining ring 14 and the parts which move therewith, the springs 21 cause the retaining ring to be moved rapidly to the left to position for closing the breech block within the gun. At this time the breech block strikes a stop or abutment 32 (Fig. 3) within the gun for limiting its further movement. Continued movement of the holding member 13 toward the stopped breech block is assisted by the action of the spring 19. At this time, the thrust elements 12 are caused to ride up the inclined surface 31 of the holding member or in other words, these thrust elements are expanded radially outward into their position for receiving thrust from the breech block and transmitting it to the breech ring of the gun as shown in Fig. 1.

Among the advantages ofithis invention may be mentioned thefact that iorthe first time a major caliber breech block-is enabled to have a substantially straight line movement'b y a simple breech mechanism capable of rapid operation. Thrust upon the breech block is transmitted through the elements'12 entirely around and in a substantially balanced condition throughout the periphery of the breech blockand the gun. The guide or guides of the breech blockare so positioned as to enable an operator or feedmechanism to insert a propelling charge into the gun without having to lift such ammunition higher than is necessary for its insertion into the gun.

Weclaim:

1. In a gun having alemovable breech block closing an. end ofabreech ringin which a propelling charge is adaptedto be located, the combination therewith of the improvementwherein said breech. block is adapted for rapid operation when in larger sizes and may be of light weight,.said improvernent including a guide along which said breech block may be moved longitudinally in a substantially straight line away fromand toward its position locked within said breech ring, a plurality of closely spaced thrust elements between an outer peripheral end face portion of said breech block and an inner end portion of said breech ring, said elements being closely spaced aroundsaid breech block andextending radially outwardly at an acute angle of substantially less than 45 to the longitudinalaxis of said breech ring, a holding member for said elements when the breech block is closed, and

'slidable outwardly to release said thrust elements from their engagement with said breech ring before opening said'breech block, the end face of said elements in contact with said breech ring and the cooperating surfaces of said breech ring in contact with the end faces of said thrust elements being tapered to allow said elements to be rotated radially. inward far enough to clear the inner edge of said breech ring as the said holding member is withdrawn from a position within said breech ring, said holding member having aledge of reduced diameter for supporting'said thrust members after their being rotated radially inward to clear said breech ring, mechanism for d I longitudinally moving said holding member and thrust members'outwardly a short distance, a retaining ring into which said holding member and thrust members are moved prior to withdrawal of said breech block from the breech ring, said retaining ring being recessed to receive said thrust members held upon said ledge of the holding member, and means whereby said'breech block retaining ring with said thrust members therein and holding member may be moved as a unit away from said breech ring to permit loading a propelling charge into said gun, said last mentioned means including said guide for said unit, a stop for said breech block when moving into a firing position Within said gun, and an inclined surface on said holding member'between said ledge and a surface on which said thrust members are held when in a thrust transmitting position for firing said gun, said inclined surface on said holding member being at an angle of less than 45 to the longitudinal axis of said breech block whereby after said breech block has engaged its stop, continued movement of the holding member for a short distance will swing said thrust members radially outwardly to engage said breech ring for transmitting a thrust upon firing from said breech block to said breech ring.

2. A gun according to claim 1 in which said mechanism includes an axial tension member for withdrawing said holding member and thrust elements from said breech ring into said retaining member, and a spring between an abutment on said tension member and said holding member for moving said holding member and thrust elements into a firingposition after said breech block has been also moved into a firing position.

3. A gun according to claim 1 in which a spring around said guide cooperates with said retaining ring unit to return it with said breech block, holding member and thrust elements to'a firing position.

References Cited in the file of this patent UNETED STATES PATENTS 2,590,981 Lippert Apr. 1, 1952 FOREIGN PATENTS 535,570 Great Britain Apr. 15, 1941 

